Floating lifting lugs for annealing cover



an-glhkw May 7, 1957 v s. G. EDELMANN FLOATING LiFTING LUGS FOR ANNEALING COVER Filed Sept. 9, 1955 TEE-.1

U W I 4 INVENTOR. SYLVESTER G. EDELMAlV/V,

his Attorney.

United States Patent C FLOATING LIFTING LUGS FOR ANNEALING COVER Sylvester G. Edelmann, Johnstown, Pa., assignor to II'Jnited States Steel Corporation, a corporation of New ersey Application September 9, 1955, Serial No. 533,320

4 Claims. (Cl. 263-49) This invention relates to corrugated sheet-metal inner covers for enclosing a stack of coiled strip or sheet steel in a controlled atmosphere while being annealed in a furnace which is usually designated as the outer cover and, more particularly, is directed to an improved connection in the nature of a floating connection between the corrugated side walls of the cover and a lifting lug for supporting the cover during movement to and from an operative covering position within the annealing furnace.

- Inner covers of the character referred to are commonly cylindrical in shape and are provided with lifting lugs on the sides thereof for engagement with the lifting hooks of a chain or cable hoist by which they are raised and lowered to and from a covering position over a stack of coils supported on the furnace hearth. In the case of corrugated inner covers which are frequently preferred because of the improvements in heat transfer and rigidity of construction provided by the corrugations in their side walls, considerable trouble has been experienced with breakage of the connection between the lifting lugs and the corrugated side walls. Inner covers are of course subjected to temperature changes over a wide range between successive annealing operations and this causes extreme thermal expansion and contraction particularly in a direction laterally or circumferentially of the side walls in covers having a corrugated construction. Since conventional lifting lugs have a rigid construction and are secured to the side walls by welded connections at laterally or circumferentially spaced points, repeated thermal expansion and contraction of the character referred to subjects the welded connections to changing stresses of a nature which frequently results in their failure or breakage.

One of the principal objects of this invention is to provide a corrugated inner cover of the character referred to with a lifting lug having a supporting connection thereon which is not aflected by thermal expansion and contraction of its side walls in response to temperature changes.

Another object is to provide an improved floating connection for a lifting lug on a corrugated annealing inner cover.

A still further object of the invention is to provide a lifting attachment for corrugated annealing inner covers which is comprised of a pair of brackets welded to laterally or peripherally spaced corrugations in the cover side wall and a lifting lug having mounting arms projecting in opposite directions therefrom which respectively have sliding supporting connections in the mounting brackets so that such brackets may move freely with the corrugations to which they are secured in response to thermal expansion and contraction of the side walls without interference from the lifting lug and its mounting arms.

Other objects and advantages of the invention will be apparent from the following description.

In the drawings, there is shown a preferred embodiment of the invention. In this showing:

Figure 1 is a side elevational view of an annealing 2,791,418 Patented May 7, 1957 2 inner cover having a lifting lug attachment constructed in accordance with the principles of this invention;

Figure 2 is a plan view of the cover shown in Figure l with a portion of the top thereof broken away and showing the corrugated construction of the cover side wall;

Figure 3 is an enlarged side elevational view of the lifting lug attachment shown in Figure 1 and a fragmentary portion of the corrugated side wall to which it is secured;

Figure 4 is a top plan view of the structure shown in Figure 3; and

Figure 5 is a sectional and elevational view taken in the plane of the line VV of Figure 3.

Figures 1 and 2 show a conventional annealing inner cover of the type to which the present invention is directed. As illustrated, the cover is cylindrical in shape and has a circular top 1, a cylindrical side Wall 2 and an annular flange 3 secured to the bottom of the side wall 2 for sealing engagement in the hearth of a furnace. To raise and lower the cover from an operative position in which it covers a stack of coil or strip supported on the hearth of an annealing furnace, a plurality of lifting lug attachments, preferably three in number and respectively designated as a whole by the numeral 4, are provided for engagement with the lifting hooks of a chain or cable hoist and are secured to the side wall 2 in a manner to be described. At points directly above each of the attachments 4, guards 5 are secured to the top 1 to protect the cover against damage by the hoist chains or cables. The side wall 2 is further protected and reinforced by peripheral reinforcing bands 6 secured thereto at vertically spaced intervals.

The side wall 2 is formed of corrugated sheet metal providing vertically extending corrugations having crests 7 along its outer periphery. As compared to the surface area of a smooth cylinder, the corrugated construction of the side wall 2 provides a much larger surface area, and it will thus be apparent that thermal expansion and contraction in response to temperature changes results in appreciable displacement of the crests 7 relative to each other. In a manner to be described, the construction of the lifting attachments 4 is such that free thermal displacement of the corrugation crests is permitted.

Referring to Figures 3, 4 and 5, each of the lifting lug attachments 4 includes a pair of U-shaped brackets 8 respectively secured to a pair of laterally or circumferentially spaced side wall corrugations at the crests 7 thereof. Each of the brackets 8 has a center portion 9 (see Figure 5) which extends lengthwise and in spaced relation with respect to the crest 7 of the corrugation to which it is secured, and a pair of arms 10 projecting inwardly from the ends of the center portion 9. As best shown in Figure 4, the outer end of each arm 10 has a scalloped recess in which a corrugation crest 7 is fitted in snug engagement therewith and a welded connection 11 securing it to such corrugation crest. Each of the brackets 8 thus defines an opening 12 which extends transversely of the corrugation crest 7 to which it is secured, the openings 12 in the pair of brackets 8 being horizontally aligned with each other.

A mounting strap 13 has end portions 14 which are received and have endwise sliding movement in the bracket opening 12. The strap 13 has an arcuate shape corresponding to the relative positions of the corrugation crests 7 so that the brackets 8 may slide in an endwise direction relative to the strap ends 14 in response to thermal expansion and contraction of the cover. The center portion of the strap 13 is enlarged to provide outwardly facing shoulders 15 for abutting engagement with the brackets 8 to limit endwise movement of the strap 13 with respect to the brackets 8. A lifting lug 16 is secured to the strap in a central position between the brackets 8. While the lug 16 is illustrated as being a metal strap shaped to provide a loop through which a lifting cable may be threaded, it will be understood other forms of lugs for lifting engagement with the hooks of chain or cable hoists may be employed and are contemplated.

In operation, the attachments 4' are employed conventionally in cooperation with a chain or cable hoist to transport the cover to and from an operative position in an annealing furnace. Attention is particularly directed to the fact that the attachments 4, by reason of the sliding support of the strap ends 14 in the bracket openings 12, have a floating support on the corrugated crests 7 which permits thermal expansion and contraction of the side wall 2 without stressing the welded connections 11. When the crests 7 move laterally or circumferentially relative to each other in response to thermal expansion or contraction of. the side Wall 2, the brackets 8 move freely in' an endwise direction with respect to the strap 13, this movement being permitted by the sliding support of the strap ends 14 in the bracket openings 12.

While one embodiment of my invention has been shown and described it will beapparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. In an annealinginner cover subject to extreme temperature changes upon movement to and from an operative position in a furnace outer cover, the combination with a sheet-metal side wall forming a part of said cover and having vertically extending corrugations therein with the crests of said corrugations spaced laterally relatively to each other, of a lifting attachment comprising a pair of supporting members having welded connections with a laterally spaced pair of said corrugation crests, a lifting lug arranged between said supporting. members, and a pair of mounting members secured to and projecting in opposite endwise directions from said lug, each of said mounting members having a slide connection with one of said supporting members which permits movement of said supporting members relative to said lugin response to thermal expansion and contraction of said side wall.

2. In an annealing inner cover subject to extreme temperature changes upon movement to and from an operative position in a furnace outer cover, the combination with a sheet-metal side wall'forrning a part of said cover and having vertically'extending corrugations therein with the crests of said corrugations spaced laterally relatively to each other, of a lifting attachment comprising a pair of brackets having welded connections with a laterally spaced pair of said corrugation crests, each of said brackets having an opening extending in a direction transversely of said corrugations, said bracket openings being aligned with each other, a mounting strap having end portions received in said bracket openings and mounting it for sliding movement relative to said brackets, said strap having spaced shoulder portions for abutting engagement with said brackets to limit its movement relative thereto, and a lifting lug secured to said strap at a point between said brackets.

3. A lifting lug support as defined in claim 2 characterized by each of said brackets comprising a U-shaped member including a center portion having arms extending inwardly from the ends thereof and spacing it from the corrugation crest to which it is secured.

4. A lifting lug support as defined in claim 3 characterized by each of said arms having a recess in its outer end for fitting engagement over said last named corrugation crest.

References Citedinthe' file of this patent UNITED STATES PATENTS 2,063,603 Hunter et al. Dec. 8, 1936 2,095,565 Lightle Oct. 12, 1937 2,161,779 Croft June 13, 1939 2,529,609 Jacob Nov. 14, 1950 

